Such crop pick-ups are, for example, used in combination with forage harvesters for picking up grass. The forage harvester drives over a swath of grass that is picked up by the grass crop pick-up and subsequently chopped by the forage harvester. The chopped grass can then be used as forage.
The current generation of New Holland forage harvesters is optionally equipped with the advanced MetaLoc™ metal detection system. This system is equipped with six detection zones which bring the infeed rolls of the forage harvester to a standstill within 300 milliseconds when metal is detected. The location of the metal is shown on a monitor, the driver stops the forage harvester and a reverse clutch flips the windguard of the crop pick-up automatically open and reverses the auger to retrieve the crop from the forage harvester. This makes it possible to remove the metal before it ends up in the cutter drum or blower of the forage harvester, where it can cause extensive damage to the forage harvester. This also prevents the metal from ending up in the forage, which would entail safety risks for the cattle.
A similar system can also be applied to other agricultural implements for picking up crops from a field, such as, for example, balers or loading wagons. Besides metal parts, other crop-foreign objects, too, like wood or rocks, can prove dangerous for the agricultural implement or the cattle which would eventually consume the picked-up crop. There are detectors available that are able to detect non-metal foreign objects in the crop flow.
It is a drawback of the current system that often, part of the crop retrieved from the forage harvester is caught in the crop pick-up between the reel and the auger. Since the crop intake is stopped as soon as the foreign object is detected, this foreign object will, in most cases, be located in that part of the crop that is still on the crop pick-up. If the driver were to start driving with the foreign object still in the crop pick-up, it is most likely that the foreign object would end up in the forage harvester once more. That is why the driver of the forage harvester has to get out first, walk up to the crop pick-up, remove the foreign object from the retrieved crop (to be found in the place shown on the monitor), walk back and get into the cab of the forage harvester, before he can continue his way. There is, therefore, a need for an improvement to the system, which makes it unnecessary for the driver to get out when a foreign object is detected.